1. Field of Invention
This invention relates to vehicle diagnostic equipment, and more particularly to a hand control adapted for use in and around vehicles in conjunction with vehicle diagnostic equipment.
2. Description of the Prior Art
The recent establishment of rigid specifications relating to emissions of internal combustion engines on vehicles, in order to reduce pollutants discharged into the atmosphere, and the desire to improve fuel economy of internal combustion engines in the light of critical oil shortages, have resulted in an ever-increasing demand for more comprehensive and more accurate diagnostic systems for vehicles, particularly for internal combustion engines therein. Systems employing electronic circuitry, usually of the analog type, in combination with a variety of displays and indicators (such as cathode ray tube displays, meters, and alarm signal lights) have achieved widespread use and have evolved to a certain degree of sophistication. However, the aforementioned new demands upon performance of internal combustion engines have fostered development of more sophisticated systems, even to the point of utilizing computers for accurately performing calculations using parameters measured by transducers and probes attached to and used with the engine under test, and computer storage and analysis of the results of one or more series of tests in order to facilitate adjustment and repair.
However, such sophisticated systems must be used in relatively harsh and unclean environments, such as high usage inspection bays, repair facilities, gas stations and the like. Additionally, the sophistication of advanced diagnostic systems inherently increases the equipment cost to the point where it is necessary to provide high usage of the diagnostic equipment in order to justify its increased cost. In order to achieve high usage, it is necessary to provide equipment which is easy to use and which promotes rapid performance of a multiplicity of different tests in a hostile environment in and around the vehicle.
When tests require operator performance near the engine, the operator must have control over the diagnostic equipment near the engine compartment of the vehicle; and when tests require actual operation of the vehicle (such as cranking or starting the engine and adjusting it to different speeds), the operator must be provided with control over the diagnostic equipment while he is seated in the driver's seat of the vehicle. It can normally be expected that the operator will have to move from one station to another in performing a variety of vehicle tests, so it is necessary to provide the operator with a control which is easily moved about, even though such control may be required to have a large amount of cable thereon. If such a control is hung in a vehicle, it must be stable and the cable thereon must not get entangled in the vehicle.